Process for assembling an electron tube electrode



1.. R. WANNER 3,483,349

PROCESS FOR ASSEMBLING AN ELECTRON TUBE ELECTRODE Dec. 9, 1969 OriginalFiled July 11, 1966 INVENTOR.

ATTORNEY LOUIS R. WANNER BY d 7" United States Patent ()fiice 3,483,349PROCESS FOR ASSEMBLING AN ELECTRON TUBE ELECTRODE Louis R. Wanner,Seneca Falls, N.Y., assignor to Sylvania Electric Products Inc., acorporation of Delaware Original application July 11, 1966, Ser. No.564,205.

Divided and this application Apr. 8, 1968, Ser.

Int. Cl. B23k 9/02, 11/02, 11/04 US. Cl. 219107 3 Claims ABSTRACT OF THEDISCLOSURE CROSS REFERENCE This invention is a division of anapplication entitled: Electron Tube Electrode, filed July 11, 1966, US.Ser. No. 564,205, in the name of the applicant of the presentapplication.

BACKGROUND OF THE INVENTION Conventional cathode ray tubes utilize atleast one electron gun structure which usually comprises a plurality oflongitudinally arrayed electrodes in spaced axial alignment. In certaintypes of electron guns, a two member electrode structure is utilized; asfor example the doubleend anode commonly employed in the low focusvoltage electron gun. A double-end structure of this type is usuallycomprised of two similarly formed cup-like elements, such as an innerand an outer member, each having an open end, an inwardly turned flangeportion in the form of a partially closed opposite end with a terminallyformed aperture therein, and a substantially cylidrical body or skirtportion integral to the flange portion. The two members differdiametrically in substantially the skirt and flange portions tofacilitate the compatible telescoping of the skirt portion of the innermember Within the skirt portion of the outer member to thereby provide adoubleend electrode having a terminally formed aperture at either end.As these apertures aid in forming the focusing lenses of the gun, it isvery important that they be in axial alignment with the other gunelectrodes. Any displacement of the apertures or unintentional tilt ofthe electrodes causes the formation of electrostatic fields which arenot axially symmetrical to the axis of the electron beam. Suchaggravating fields distort the shape of the electron beam and result indegradation of picture quality.

The fabrication of the described substantially cylindrical inner andouter members is usually accomplished by a drawing operation wherein itis necessary to have a slight longitudinal diametrical divergence in theparts to facilitate withdrawal of the male die portion. Parts formed inthis manner evidence a slightly larger diameter at the open end than atthe inwardly turned flange portion of the aperture end. Thus, theachievement of accurate alignment through the telescopic assembly ofsuch parts is a diflicult operation due to the presence of diametricaldivergences and manufacturing tolerances.

A conventional bonding procedure for joining the telescoped members isone wherein transverse welding is 3,483,349 Patented Dec. 9, 1969utilized diametrically across the assembly. The diametrical pressurenecessary, in this welding procedure, to bond the assembled membersaggravates the misalignment situation. If, on the other hand, thetransverse Welding pressure is insufficient to effect electrical contactbetween the assembled member, inadequate jointure of the assemblyresults. Because of the normal tolerances of the telescoped members, thefirst weld tends to tilt the inner member in an off-axial direction andsubsequent welds sequentially applied promote out-of-roundness of theassembled structure. Thus, misalignment of the two-member double-endelectrode has been a troublesome problem in eletcron gun constructionresulting in a considerable number of alignment rejects.

OBJECTS AND SUMMARY OF THE INVENTION It is an object of the invention toreduce the af0rementioned disadvantages and to improve the fabricationof telescoped two-member electrode assemblies.

Another object is to provide means for improved alignment and jointurethat are integral to the parts assembled.

Further objects are to reduce the number of alignment and jointurerejects occurring from the critical construction of the two-member,double end electrode assembly.

The foregoing objects are achieved in one aspect of the invention by theprovision of a double-end electrode structure formed of two compatiblyformed cup-like members each having a leading edge, a skirt portion andan inwardly turned flange portion with a related aperture axiallyoriented therein. The leading edge and skirt portion of the cup-likeinner member are telescoped within the skirt portion of the cup-likeouter member. The telescoping movement therebetween is limited byabutment of the leading edge of the inner member with a plurality ofspaced-apart like protnberances extending interiorly from the inwardlyturned flange portion of the outer member whereat jointure is effectedto provide desired alignment of the two members and the respectiveapertures therein.

For. a better understanding of the present invention, together withother and further objects, advantages, and capabilities thereof,reference is made to the following specification and appended claims inconnection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a diagrammatic viewshowing an electron gun as utilized in a cathode ray tube;

FIGURE 2 is a sectional view showing one embodiment of the invention;

FIGURE 3 is a sectional view showing another embodiment of theinvention; and

FIGURE 4 is a sectioned view showing means for assembling the two memberelectrode structure of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGURE 1 there is shown atypical electron gun 11 as utilized in a conventional cathode ray tubewherein a plurality of cooperating electrodes are spaced andelectrically energized to form and control desired electron beam 15.Electron generators of this construction may be incorporatedindividually or plurally within many types of cathode ray tubesdepending upon the nature of the display function desired.

In greater detail, the electron gun 11 is shown as comprising anelectron beam source 17 having electron emissive material 19 depositedthereon in a manner that the electrons emitted therefrom will formelectron beam 15. Spaced from the electron source 17 and positioned insequential concentrical array along the path of electron travel are anumber of cooperating electrodes such as: a

first apertured grid 21, a second apertured grid 23, an electronaccelerating anode 25 having a first lens cup 27 with an axial aperture29 therein and a second lens cup 31 with an axial aperture 33 therein,an electrostatic focusing electrode 35, and a fiinal anode structure 37having a lens cup 39 with an aperture 40 therein.

Accurate coaxial alignment of the respective apertures of the severalelectron gun electrodes is essential for desired operational efiiciency.The electron beam 15, which is directed and made convergent to provide aspot of minimum diameter on a cathodoluminescent screen, not shown, isfocused by the electron lens formed by the focusing assembly 47 whichcomprises the final anode lens cup 39 and the second anode lens cup 31spacedly encompassed by the focusing electrode 35. Partial prefocusingand beam acceleration is furnished by the anode first lens cup 27 incooperation with apertural configurations and spacings of the precedingfirst and second grids 21 and 23 respectively.

With reference to FIGURE 2, the accelerating anode 25, in this instance,is a two-member double-end apertured electrode structure wherein thefirst or outer member 26, containing the first lens cup 27, must beproperly mated with the second or inner member 30, containing secondlens cup 31, to produce the desired coaxial alignment of the respectiveapertures 29 and 33 therein.

It will be noted that the outer member 26 has a skirt portion 45 havinga leading edge 47 and an oppositely disposed integral inwardly turnedflanged portion 49 merging to a diametrically reduced first lens cupportion 27 having the related aperture 29 therein. Extending interiorlyfrom the flanged portion are a plurality of at least three spaced-apartlike protuberances 51. Extending exteriorly from the skirt portion are aplurality of electrode support studs 52, of which two are shown. Theseare bonded to the skirt portion, such as by Welding, and are utilized tosupport the completed anode in the electron gun 11 by means not shown.

Telescoped Within the aforementioned outer member 26 is a compatiblyformed inner member 30 having a skirt portion 53 with a leading edge 55therearound and an oppositely disposed integral inwardly turned flangeportion 57 having a diametrically reduced second lens cup portion 31with the related aperture 33 therein. The telescoping movement of theskirt portion 53 of the inner member 30 within the skirt portion 45 ofthe outer member 26 is limited by portions of the leading edge 55 of theinner member abutting the interiorly extending protuberances 51 of theouter member. It has been found that the discrete plural-point contactof the inner member with the several interior protuberances of the outermember markedly improves the desired axial alignment of the two memberscomprising the dual apertured anode structure 25. In addition, jointurebetween the two telescoped members at the abutment areas is achieved inan improved manner to promote and preserve the desired alignmentprovided by the aforedescribed abutment.

In referring to FIGURE 4, there is shown the accelerating anode assembly25 whereof the inner member 30 is compatibly telescoped within the outermember 26 from which outwardly extends a plurality of support studs 52.With the leading edge 55 of the inner member abutting the interiorprotuberances 51 of the outer member, the anode assembly is suitablypositioned in a bonding device 61. In this instance, bonding is effectedby welding, and the device utilized comprises a first 'Welding electrodestructure 63 of a suitable electrically conductive material, such ascopper or an alloy thereof, having a welding surface 65 with a recess 67therein formed to diametrically accommodate the first lens cup portion27 of the outer member 26 by a sliding fit therein. In this manner theouter member is suitably oriented in the first welding electrode withthe flange portion 49 being in contact with the electrode weldingsurface 65.

The bonding device has an insulative shell-like member 69, as of hardnylon, conjunctively associated with the first electrode structure 63,with an upstanding wall 70 formed to define a cavity 71 which isdimensioned to spacedly accommodate the anode assembly 25 and itsoutwardly extending support studs 52.

A second electrode structure 75 of a suitable electrically conductivematerial, such as copper or an alloy thereof, is dimensioned to slidablyfit within the upstanding insulative wall 70. This second electrode hasa welding surface 77 with a recess 79 formed therein to diametricallyaccommodate the second lens cup portion 31 of the inner member 30 by asliding fit therein. Thus, the inner mem her is oriented in the secondwelding electrode with the flange portion 57 being in contact with thewelding surface 77. The second electrode structure also has cut-out orrecess provisions to spacedly accommodate the support studs on the outermember of the anode assembly.

With the telescoped anode assembly so positioned in the welding device61, axial pressure is applied to the first and second electrodestructures in the directions as indicated by arrows A and B in FIGURE 4,by means not shown. It will be noted that the axial pressure istransferred to the flanged portions of the respective telescopedmembers. This axial pressure effects positive abutment contact betweenportions of the leading edge of the inner member with the inwardlyextending protuberances of the outer member.

When suflicient pressure is applied in an axial manner to make thedesired alignment and abutment contact between the two members, awelding potential is supplied to the respective first and second weldingelectrode structure 63 and 75 by a connected welding power supply 81through the activation of electrical switching means 83. Thus,multi-point juncture is consummated, and the desired axial alignment ofthe apertures in the telescoped two-member double-end electrode assemblyis achieved in an improved fabrication manner.

Another embodiment of the invention utilizing pressured abutment isshown in FIGURE 3 wherein the outer member 26' has an inwardly turnedflange portion 49' with no protuberances extending interiorly therefrom;instead, the inner portion 30' has a plurality of spacedapart likeprojections extending linearly from the leading edge 55' to be indiscrete abutment and jointure with portions of the inwardly turnedflange portion 49 of the louter member. Such projections are at leastthree in num- Use of the alignment and jointure means of this invention,along with the method of assembling the two member electrode structure,results in a vastly improved double-end anode that has desired aperturalalignment, and one that is not diametrically deformed duringfabrication. Positive alignment and multiple-point bonding effect anelectron gun electrode structure that is definitely superior to priorart telescoped electrodes that have been transversely weldeddiametrically across the assembly.

While there have been shown and described what are at present consideredthe preferred embodiments of the invention, it will be obvious to thoseskilled in the art that various changes and modifications may be madetherein without departing from the scope of the invention as defined bythe appended claims.

I claim:

1. A process for assembling a two-member electron tube electrodestructure having apertures at both ends thereof wherein an aperturedinner cup-like member having a skirt-portion, an inwardly turned flangeportion, and a leading edge, has the skirt-portion telescoped within acompatibly formed apertured outer cup-like member also having a skirtportion and an inwardly turned flange portion, said process comprisingthe steps of:

positioning said inner and outer members with said skirts thereof intelescoped relationship with the telescoping movement therebetween beinglimited by at least three spaced apart portions of said leading edge 5 6of said inner member'abutting on at least three 3. The assemblingprocess according to claim 1 Wherespaced apart portions of the interiorsurface of said in said jointure is consummated at the respectiveforward inwardly turned flanged portion of said outer memedges of atleast three spaced-apart like projections extendber; ing linearlyv fromthe leading edge of said inner member applying axial pressure againstsubstantially only the skirt portion to make discrete seating contact onportions exterior surface of each of said inwardly turned of theinterior surface of said inwardly turned flange porflange portion ofsaid telescoped members to effect tion of said outer member. positiveseated abutment on said discrete areas of contact therebetween; andReferences Cited making electrical contact with the exterionsurface of10 UNITED STATES PATENTS each of sald lnwardly turned flange portion ofsaid pressured telescoped members to complete a welding cf g circuit toconsummate jointure of said members at 04540 11/1908 L chona "Tsubstantially said discrete abutment contact areas to 3 2 7/1909 is gi 2provide correct alignment of said electrode members 15 3 1 5/1967Burdick et a1. 31382 and said apertures therein.

2. The assembling process according to claim 1 Wherein said jointure isconsummated at points Where the lead- JOSEPH TRUHE Pnmary Exammer ingedge of the skirt portion of said inner member makes L. H. BENDER,Assistant Examiner discrete seating contact on at least threespaced-apart like 20 protuberances extending interiorly from said flangeportion of said outer member. 21993

